Human bones are continuously remodelling through the repeated process of resorption and reconstitution. In the process, osteoblasts and osteoclasts are considered to be the cells mainly in charge of bone formation and bone resorption, respectively. Thus, bone formation is promoted by stimulating the growth, differentiation, or activation of osteoblasts. Osteoblasts differentiate into osteocytes which are cells surrounded by a mineralized matrix. Very little is known about the mechanisms directing the differentiation of the osteoprogenitors into osteoblasts, but it is clear that there is a fine balance between different cellular stages that control osteoblastic cell renewal and cell loss.